This invention relates to voltage regulators operable over a wide range of input voltages and which regulate an output voltage by variable cycle modulation of the input voltage.
The regulator basically comprises a transistor switching means connected between an unregulated input source and an output terminal at which a load is connectable. The switching means is switched on and off at a high frequency by a circuit comprised of a charge storage means operating in accordance with the input voltage level. This charge storage circuit is periodically discharged by an oscillatory circuit comprising another charge storage circuit operating in accordance with the output voltage. The resulting output of the switching means is integrated in a low pass filter circuit which includes the primary winding of a transformer to derive an average value which is the output voltage of the regulator. The transformer secondary winding is coupled to the output terminal through a unidirectional current element so that turn off transients of the switching means inductively couple energy by means of the transformer onto the output terminal to maintain the voltage thereat. The circuit is so designed that the duty cycle of the wave traversing the switching means is related to the input voltage while the pulse rate of the rectangular wave is related to the output regulated voltage.
The purpose of the invention is to provide a regulated voltage given an unregulated voltage which can vary over an extremely wide range.